Mandibular Explant Assay for Investigating Extrinsic Stimuli on Bone and Cartilage Development

A major issue in developmental biology is to determine how embryonic tissues respond to molecular signals in a timely manner and given the position-restricted instructions during morphogenesis, of which Meckel's cartilage is a classical example. The ex-vivo explant model is a practical and convenient system that allows investigation of bone and cartilage responses to specific stimuli under a controlled manner that closely mimics the in vivo conditions. In this protocol, the explant model was applied to test whether Meckel's cartilage and surrounding tissues are responsive to the Endothelin1 (Edn1) signaling molecule and whether it would rescue the phenotype of genetic mutations. The system allows a high degree of manipulation in terms of the concentrations of exogenous compounds added to the explant, time points with regards to measuring mandibular development, and the method of application of exogenous molecules and teratogens.